(a) Technical Field
Embodiments of the present disclosure are directed to a method of excimer laser annealing.
(b) Discussion of the Related Art
Excimer laser annealing (ELA) can be used to form transistors used for switches or driving circuits of display devices, such as an organic light emitting display device and a liquid crystal display device. In an ELA method, an excimer laser beam is irradiated to an amorphous semiconductor film formed on a substrate to locally heat and melt the amorphous semiconductor film and thereafter, crystallize the corresponding amorphous semiconductor film into a polycrystalline semiconductor film while cooling the heated amorphous semiconductor film. The crystallized semiconductor film can form a high performance transistor because of increased electron mobility.
Therefore, ELA is used for modern mass production of display devices. For manufacturing uniformity of the transistors of the display devices, the polycrystalline semiconductor film formed by ELA should be uniform. To improve the uniformity and electrical characteristics of the semiconductor film, rectangular grains may be formed. ELA control factors include energy density, the number of overlapping pulses, pulse duration, an incidence angle, a substrate temperature, etc.